A second thought,  users gets it's info from /var/run/utmp but that isn't always accurate (on my system users says nothing even though I'm certainly logged on to it). Try ps -ef | grep alien-os to see what tasks are running as it.

Chris

From the man page for bash:

When  bash  is  invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands
from the file /etc/profile, if that file exists.  After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and  ~/.profile,  in  that
order,  and  reads  and  executes  commands  from the first one that exists and is readable.

So if there is a .bashrc on the system .profile will be ignored (unless I've misread that).

Chris

I've not used sudo for passwordless access for quite a few years. But as far as I can remember:

It should not make any difference whether you logged onto wolke7 through ssh or directly on to it.

Start by running sudo -l on wolke7 and see what it says you can do.

Once you can run it locally without being asked for a password ssh os@192.168.255.42 '/sbin/wondershaper eth0 1500 750' should work.

Chris

Where is root's home directory? head -1 /etc/passwd should show you.

If that's / then root's files such as .cache would end up there.

Chris

How thoroughly frozen is it?

Does ctrl-alt-f1 get you to a text console when it's hung?
Can you log on from another system (if you have one)? If it's only the GUI that's hung you should be able to investigate then. If that session hangs as well set it running top etc before starting blender and the last screenful should be readable on the other system.
Does pressing caps/num/scroll lock light up the LED on the keyboard.
Does ctrl-alt-del have any affect?
Does the reset button reboot the system? I'd not expect a software bug to stop that.

Chris

I think the number in "udevd[*number*]" is the PID of the udevd task. Run ps -ef | grep udev and see if the PID matches.

On my system /etc/modprobe.d/nvidia.conf contains

install nvidia modprobe -i nvidia-current $CMDLINE_OPTS

install nvidia-modeset modprobe nvidia ; modprobe -i nvidia-current-modeset $CMDLINE_OPTS

install nvidia-drm modprobe nvidia-current-modeset ; modprobe -i nvidia-current-drm $CMDLINE_OPTS

install nvidia-uvm modprobe nvidia ; modprobe -i nvidia-current-uvm $CMDLINE_OPTS

remove nvidia modprobe -r -i nvidia-drm nvidia-modeset nvidia-uvm nvidia

# These aliases are defined in *all* nvidia modules.
# Duplicating them here sets higher precedence and ensures the selected
# module gets loaded instead of a random first match if more than one
# version is installed. See #798207.
alias   pci:v000010DEd00000E00sv*sd*bc04sc80i00*        nvidia
alias   pci:v000010DEd00000AA3sv*sd*bc0Bsc40i00*        nvidia
alias   pci:v000010DEd*sv*sd*bc03sc02i00*               nvidia
alias   pci:v000010DEd*sv*sd*bc03sc00i00*               nvidia

But I've not rebooted it for a while and I can't remember if I got that message when I did.

Chris

You can set up entries in /etc/sudoers to let members of a given group (or specific individuals) run specific commands via sudo without asking for a password. See the man page for sudoers for examples (and caveats).

Note that it's often safer to let them run a script you've written as root since the script can do any necessary checks before doing anything dangerous.

Chris

Also run the dist-upgrade with --simulate first (this tell you what it will do but does not do anything).

Chris

I would advise you to truncate  /usr/lib/cups/notifier/error_log if it's getting too big:
>  /usr/lib/cups/notifier/error_log

rm will remove the directory entry, but won't free space if something still has the file open. You might be able to find it by looking in /proc (it will be in a directory of the PID of the task that has it open) and truncate it there. Otherwise restarting the task(s) will free the space (if all else fails a reboot restarts everything).

Chris

PS. I learnt that in the college of hard knocks.

The ? means that polkitd isn't attached to a terminal. ps aux gives more information:

chris@rigel:~/bin$ ps aux | grep polkit
chris      360  0.0  0.0  12784   972 pts/2    S+   17:25   0:00 grep polkit
root      2787  0.0  0.1 297264  6992 ?        Sl    2018   0:00 /usr/lib/policykit-1/polkitd --no-debug

chris@rigel:~/bin$ ps aux | head -3
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0  15812  1628 ?        Ss    2018   2:25 init [2]
root         2  0.0  0.0      0     0 ?        S     2018   0:05 [kthreadd]

The second command is just to show the column headings. The first column shows polkit runs as root which is why you need ps ax to show it.

Chris

If you need to ask questions like that the three safest options are:

1: Keep it all in your head. And only discuss it face to face when safe from listening devices.

2: Only use pencil and paper etc, not computers.

3: Only use computers that are never connected to the internet at all. And be very careful if you need to copy data from the internet onto them, eg burn it to CD/DVD on an internet connected system, read it on the safe system, then destroy the disk to ensure data can't ever get out.

And think carefully about the threat model if you need to resort to any of the above options.

Chris

If you have more than 1 system try ping, ssh, etc from another system to see if the hung system responds.

Does pressing caps/num/shift lock turn on the light on the keyboard?

Do any of the lights on the motherboard or NIC show anything significant (if the light's usually on when it's working and off when it's sleeping what does it show when the systems hung?)

Chris